An efficient sampling strategy for selection of biobank samples using risk scores

Intrauterine exposure to perfluorinated compounds and overweight at age 4: A case-control study

Aims

The aims were to investigate the association between maternal serum levels of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS) and perfluorononanoic acid (PFNA) in early pregnancy and overweight in the child at 4 years and to assess potential heterogeneity in exposure effect between strata with different levels of other risk factors for overweight.

Methods

We used a case-control design and included 354 cases (ISO-BMI ≥ 18 kg/m²) and 2 controls per case (ISO-BMI ≤17 kg/m²) from child health care centers in Malmö, Sweden. Controls were selected stratified on risk scores for overweight in a propensity score framework. Maternal serum levels were analyzed in biobanked samples collected by routine around gestational week 14. Logistic regression was used to estimate odds ratios between quartiles of maternal serum levels and child overweight at age 4.

Results

There were no consistent monotonic exposure-response relationships. We found some significant odds ratios in specific quartiles but these were regarded as spurious findings. The absence of an effect was consistent over risk strata.

Conclusions

We did not find evidence of an association between maternal serum levels of PFOS, PFOA, PFHxS and PFNA in early pregnancy and child overweight at age 4. The level of other risk factors for overweight did not affect children’s susceptibility to prenatal PFAS exposure.